Which one of the following statement pertaining to pollutants is correct?

Non-biodegradable pollutant: a pollutant which retains its toxicity for extremely long periods of time. Some lead and mercury compounds, certain chlorinated hydrocarbon pesticides (e.g., DDT) and radioactive substances are nonbiodegradable pollutants. Osteoporosis is a condition that is characterized by a decrease in bone mass and density, causing bones to become fragile. Blackfoot disease (BFD) is a severe form of peripheral vascular disease (PVD), in which the blood vessels in the lower limbs are severely damaged, resulting eventually in progressive gangrene. It has been observed in Taiwan. Itai-itai disease is a chronic cadmium poisoning with renal tubular dysfunction followed by osteomalacia.